// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
 *
 * Description: CoreSight Program Flow Trace driver
 */

#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/sysfs.h>
#include <linux/stat.h>
#include <linux/pm_runtime.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/coresight.h>
#include <linux/coresight-pmu.h>
#include <linux/amba/bus.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/clk.h>
#include <linux/perf_event.h>
#include <linux/perf/arm_pmu.h>
#include <asm/sections.h>

#include "coresight-etm.h"
#include "coresight-etm-perf.h"
#include "coresight-trace-id.h"

/*
 * Not really modular but using module_param is the easiest way to
 * remain consistent with existing use cases for now.
 */
static int boot_enable;
module_param_named(boot_enable, boot_enable, int, S_IRUGO);

static struct etm_drvdata *etmdrvdata[NR_CPUS];

static enum cpuhp_state hp_online;

/*
 * Memory mapped writes to clear os lock are not supported on some processors
 * and OS lock must be unlocked before any memory mapped access on such
 * processors, otherwise memory mapped reads/writes will be invalid.
 */
static void etm_os_unlock(struct etm_drvdata *drvdata)
{
        /* Writing any value to ETMOSLAR unlocks the trace registers */
        etm_writel(drvdata, 0x0, ETMOSLAR);
        drvdata->os_unlock = true;
        isb();
}

static void etm_set_pwrdwn(struct etm_drvdata *drvdata)
{
        u32 etmcr;

        /* Ensure pending cp14 accesses complete before setting pwrdwn */
        mb();
        isb();
        etmcr = etm_readl(drvdata, ETMCR);
        etmcr |= ETMCR_PWD_DWN;
        etm_writel(drvdata, etmcr, ETMCR);
}

static void etm_clr_pwrdwn(struct etm_drvdata *drvdata)
{
        u32 etmcr;

        etmcr = etm_readl(drvdata, ETMCR);
        etmcr &= ~ETMCR_PWD_DWN;
        etm_writel(drvdata, etmcr, ETMCR);
        /* Ensure pwrup completes before subsequent cp14 accesses */
        mb();
        isb();
}

static void etm_set_pwrup(struct etm_drvdata *drvdata)
{
        u32 etmpdcr;

        etmpdcr = readl_relaxed(drvdata->csa.base + ETMPDCR);
        etmpdcr |= ETMPDCR_PWD_UP;
        writel_relaxed(etmpdcr, drvdata->csa.base + ETMPDCR);
        /* Ensure pwrup completes before subsequent cp14 accesses */
        mb();
        isb();
}

static void etm_clr_pwrup(struct etm_drvdata *drvdata)
{
        u32 etmpdcr;

        /* Ensure pending cp14 accesses complete before clearing pwrup */
        mb();
        isb();
        etmpdcr = readl_relaxed(drvdata->csa.base + ETMPDCR);
        etmpdcr &= ~ETMPDCR_PWD_UP;
        writel_relaxed(etmpdcr, drvdata->csa.base + ETMPDCR);
}

/**
 * coresight_timeout_etm - loop until a bit has changed to a specific state.
 * @drvdata: etm's private data structure.
 * @offset: address of a register, starting from @addr.
 * @position: the position of the bit of interest.
 * @value: the value the bit should have.
 *
 * Basically the same as @coresight_timeout except for the register access
 * method where we have to account for CP14 configurations.
 *
 * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
 * TIMEOUT_US has elapsed, which ever happens first.
 */

static int coresight_timeout_etm(struct etm_drvdata *drvdata, u32 offset,
                                  int position, int value)
{
        int i;
        u32 val;

        for (i = TIMEOUT_US; i > 0; i--) {
                val = etm_readl(drvdata, offset);
                /* Waiting on the bit to go from 0 to 1 */
                if (value) {
                        if (val & BIT(position))
                                return 0;
                /* Waiting on the bit to go from 1 to 0 */
                } else {
                        if (!(val & BIT(position)))
                                return 0;
                }

                /*
                 * Delay is arbitrary - the specification doesn't say how long
                 * we are expected to wait.  Extra check required to make sure
                 * we don't wait needlessly on the last iteration.
                 */
                if (i - 1)
                        udelay(1);
        }

        return -EAGAIN;
}


static void etm_set_prog(struct etm_drvdata *drvdata)
{
        u32 etmcr;

        etmcr = etm_readl(drvdata, ETMCR);
        etmcr |= ETMCR_ETM_PRG;
        etm_writel(drvdata, etmcr, ETMCR);
        /*
         * Recommended by spec for cp14 accesses to ensure etmcr write is
         * complete before polling etmsr
         */
        isb();
        if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 1)) {
                dev_err(&drvdata->csdev->dev,
                        "%s: timeout observed when probing at offset %#x\n",
                        __func__, ETMSR);
        }
}

static void etm_clr_prog(struct etm_drvdata *drvdata)
{
        u32 etmcr;

        etmcr = etm_readl(drvdata, ETMCR);
        etmcr &= ~ETMCR_ETM_PRG;
        etm_writel(drvdata, etmcr, ETMCR);
        /*
         * Recommended by spec for cp14 accesses to ensure etmcr write is
         * complete before polling etmsr
         */
        isb();
        if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 0)) {
                dev_err(&drvdata->csdev->dev,
                        "%s: timeout observed when probing at offset %#x\n",
                        __func__, ETMSR);
        }
}

void etm_set_default(struct etm_config *config)
{
        int i;

        if (WARN_ON_ONCE(!config))
                return;

        /*
         * Taken verbatim from the TRM:
         *
         * To trace all memory:
         *  set bit [24] in register 0x009, the ETMTECR1, to 1
         *  set all other bits in register 0x009, the ETMTECR1, to 0
         *  set all bits in register 0x007, the ETMTECR2, to 0
         *  set register 0x008, the ETMTEEVR, to 0x6F (TRUE).
         */
        config->enable_ctrl1 = ETMTECR1_INC_EXC;
        config->enable_ctrl2 = 0x0;
        config->enable_event = ETM_HARD_WIRE_RES_A;

        config->trigger_event = ETM_DEFAULT_EVENT_VAL;
        config->enable_event = ETM_HARD_WIRE_RES_A;

        config->seq_12_event = ETM_DEFAULT_EVENT_VAL;
        config->seq_21_event = ETM_DEFAULT_EVENT_VAL;
        config->seq_23_event = ETM_DEFAULT_EVENT_VAL;
        config->seq_31_event = ETM_DEFAULT_EVENT_VAL;
        config->seq_32_event = ETM_DEFAULT_EVENT_VAL;
        config->seq_13_event = ETM_DEFAULT_EVENT_VAL;
        config->timestamp_event = ETM_DEFAULT_EVENT_VAL;

        for (i = 0; i < ETM_MAX_CNTR; i++) {
                config->cntr_rld_val[i] = 0x0;
                config->cntr_event[i] = ETM_DEFAULT_EVENT_VAL;
                config->cntr_rld_event[i] = ETM_DEFAULT_EVENT_VAL;
                config->cntr_val[i] = 0x0;
        }

        config->seq_curr_state = 0x0;
        config->ctxid_idx = 0x0;
        for (i = 0; i < ETM_MAX_CTXID_CMP; i++)
                config->ctxid_pid[i] = 0x0;

        config->ctxid_mask = 0x0;
        /* Setting default to 1024 as per TRM recommendation */
        config->sync_freq = 0x400;
}

void etm_config_trace_mode(struct etm_config *config)
{
        u32 flags, mode;

        mode = config->mode;

        mode &= (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER);

        /* excluding kernel AND user space doesn't make sense */
        if (mode == (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER))
                return;

        /* nothing to do if neither flags are set */
        if (!(mode & ETM_MODE_EXCL_KERN) && !(mode & ETM_MODE_EXCL_USER))
                return;

        flags = (1 << 0 |       /* instruction execute */
                 3 << 3 |       /* ARM instruction */
                 0 << 5 |       /* No data value comparison */
                 0 << 7 |       /* No exact mach */
                 0 << 8);       /* Ignore context ID */

        /* No need to worry about single address comparators. */
        config->enable_ctrl2 = 0x0;

        /* Bit 0 is address range comparator 1 */
        config->enable_ctrl1 = ETMTECR1_ADDR_COMP_1;

        /*
         * On ETMv3.5:
         * ETMACTRn[13,11] == Non-secure state comparison control
         * ETMACTRn[12,10] == Secure state comparison control
         *
         * b00 == Match in all modes in this state
         * b01 == Do not match in any more in this state
         * b10 == Match in all modes excepts user mode in this state
         * b11 == Match only in user mode in this state
         */

        /* Tracing in secure mode is not supported at this time */
        flags |= (0 << 12 | 1 << 10);

        if (mode & ETM_MODE_EXCL_USER) {
                /* exclude user, match all modes except user mode */
                flags |= (1 << 13 | 0 << 11);
        } else {
                /* exclude kernel, match only in user mode */
                flags |= (1 << 13 | 1 << 11);
        }

        /*
         * The ETMEEVR register is already set to "hard wire A".  As such
         * all there is to do is setup an address comparator that spans
         * the entire address range and configure the state and mode bits.
         */
        config->addr_val[0] = (u32) 0x0;
        config->addr_val[1] = (u32) ~0x0;
        config->addr_acctype[0] = flags;
        config->addr_acctype[1] = flags;
        config->addr_type[0] = ETM_ADDR_TYPE_RANGE;
        config->addr_type[1] = ETM_ADDR_TYPE_RANGE;
}

#define ETM3X_SUPPORTED_OPTIONS (ETMCR_CYC_ACC | \
                                 ETMCR_TIMESTAMP_EN | \
                                 ETMCR_RETURN_STACK)

static int etm_parse_event_config(struct etm_drvdata *drvdata,
                                  struct perf_event *event)
{
        struct etm_config *config = &drvdata->config;
        struct perf_event_attr *attr = &event->attr;
        u8 ts_level;

        if (!attr)
                return -EINVAL;

        /* Clear configuration from previous run */
        memset(config, 0, sizeof(struct etm_config));

        if (attr->exclude_kernel)
                config->mode = ETM_MODE_EXCL_KERN;

        if (attr->exclude_user)
                config->mode = ETM_MODE_EXCL_USER;

        /* Always start from the default config */
        etm_set_default(config);

        /*
         * By default the tracers are configured to trace the whole address
         * range.  Narrow the field only if requested by user space.
         */
        if (config->mode)
                etm_config_trace_mode(config);

        config->ctrl = 0;

        if (ATTR_CFG_GET_FLD(attr, cycacc))
                config->ctrl |= ETMCR_CYC_ACC;

        ts_level = max(ATTR_CFG_GET_FLD(attr, timestamp),
                       ATTR_CFG_GET_FLD(attr, deprecated_timestamp));

        if (ts_level > 1) {
                dev_dbg(&drvdata->csdev->dev,
                        "timestamp format attribute should be 0 (off) or 1 (on)\n");
                return -EINVAL;
        }

        if (ts_level)
                config->ctrl |= ETMCR_TIMESTAMP_EN;

        /*
         * Possible to have cores with PTM (supports ret stack) and ETM (never
         * has ret stack) on the same SoC. So only enable when it can be honored
         * - trace will still continue normally otherwise.
         */
        if (ATTR_CFG_GET_FLD(attr, retstack) &&
            (drvdata->etmccer & ETMCCER_RETSTACK))
                config->ctrl |= ETMCR_RETURN_STACK;

        return 0;
}

static int etm_enable_hw(struct etm_drvdata *drvdata)
{
        int i, rc;
        u32 etmcr;
        struct etm_config *config = &drvdata->config;
        struct coresight_device *csdev = drvdata->csdev;

        CS_UNLOCK(drvdata->csa.base);

        rc = coresight_claim_device_unlocked(csdev);
        if (rc)
                goto done;

        /* Turn engine on */
        etm_clr_pwrdwn(drvdata);
        /* Apply power to trace registers */
        etm_set_pwrup(drvdata);
        /* Make sure all registers are accessible */
        etm_os_unlock(drvdata);

        etm_set_prog(drvdata);

        etmcr = etm_readl(drvdata, ETMCR);
        /* Clear setting from a previous run if need be */
        etmcr &= ~ETM3X_SUPPORTED_OPTIONS;
        etmcr |= drvdata->port_size;
        etmcr |= ETMCR_ETM_EN;
        etm_writel(drvdata, config->ctrl | etmcr, ETMCR);
        etm_writel(drvdata, config->trigger_event, ETMTRIGGER);
        etm_writel(drvdata, config->startstop_ctrl, ETMTSSCR);
        etm_writel(drvdata, config->enable_event, ETMTEEVR);
        etm_writel(drvdata, config->enable_ctrl1, ETMTECR1);
        etm_writel(drvdata, config->fifofull_level, ETMFFLR);
        for (i = 0; i < drvdata->nr_addr_cmp; i++) {
                etm_writel(drvdata, config->addr_val[i], ETMACVRn(i));
                etm_writel(drvdata, config->addr_acctype[i], ETMACTRn(i));
        }
        for (i = 0; i < drvdata->nr_cntr; i++) {
                etm_writel(drvdata, config->cntr_rld_val[i], ETMCNTRLDVRn(i));
                etm_writel(drvdata, config->cntr_event[i], ETMCNTENRn(i));
                etm_writel(drvdata, config->cntr_rld_event[i],
                           ETMCNTRLDEVRn(i));
                etm_writel(drvdata, config->cntr_val[i], ETMCNTVRn(i));
        }
        etm_writel(drvdata, config->seq_12_event, ETMSQ12EVR);
        etm_writel(drvdata, config->seq_21_event, ETMSQ21EVR);
        etm_writel(drvdata, config->seq_23_event, ETMSQ23EVR);
        etm_writel(drvdata, config->seq_31_event, ETMSQ31EVR);
        etm_writel(drvdata, config->seq_32_event, ETMSQ32EVR);
        etm_writel(drvdata, config->seq_13_event, ETMSQ13EVR);
        etm_writel(drvdata, config->seq_curr_state, ETMSQR);
        for (i = 0; i < drvdata->nr_ext_out; i++)
                etm_writel(drvdata, ETM_DEFAULT_EVENT_VAL, ETMEXTOUTEVRn(i));
        for (i = 0; i < drvdata->nr_ctxid_cmp; i++)
                etm_writel(drvdata, config->ctxid_pid[i], ETMCIDCVRn(i));
        etm_writel(drvdata, config->ctxid_mask, ETMCIDCMR);
        etm_writel(drvdata, config->sync_freq, ETMSYNCFR);
        /* No external input selected */
        etm_writel(drvdata, 0x0, ETMEXTINSELR);
        etm_writel(drvdata, config->timestamp_event, ETMTSEVR);
        /* No auxiliary control selected */
        etm_writel(drvdata, 0x0, ETMAUXCR);
        etm_writel(drvdata, drvdata->traceid, ETMTRACEIDR);
        /* No VMID comparator value selected */
        etm_writel(drvdata, 0x0, ETMVMIDCVR);

        etm_clr_prog(drvdata);

done:
        CS_LOCK(drvdata->csa.base);

        dev_dbg(&drvdata->csdev->dev, "cpu: %d enable smp call done: %d\n",
                drvdata->cpu, rc);
        return rc;
}

struct etm_enable_arg {
        struct etm_drvdata *drvdata;
        int rc;
};

static void etm_enable_sysfs_smp_call(void *info)
{
        struct etm_enable_arg *arg = info;
        struct coresight_device *csdev;

        if (WARN_ON(!arg))
                return;

        csdev = arg->drvdata->csdev;
        if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) {
                /* Someone is already using the tracer */
                arg->rc = -EBUSY;
                return;
        }

        arg->rc = etm_enable_hw(arg->drvdata);

        /* The tracer didn't start */
        if (arg->rc)
                coresight_set_mode(csdev, CS_MODE_DISABLED);
}

static int etm_cpu_id(struct coresight_device *csdev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        return drvdata->cpu;
}

void etm_release_trace_id(struct etm_drvdata *drvdata)
{
        coresight_trace_id_put_cpu_id(drvdata->cpu);
}

static int etm_enable_perf(struct coresight_device *csdev,
                           struct perf_event *event,
                           struct coresight_path *path)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
        int ret;

        if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
                return -EINVAL;

        if (!coresight_take_mode(csdev, CS_MODE_PERF))
                return -EBUSY;

        /* Configure the tracer based on the session's specifics */
        etm_parse_event_config(drvdata, event);
        drvdata->traceid = path->trace_id;

        /* And enable it */
        ret = etm_enable_hw(drvdata);

        /* Failed to start tracer; roll back to DISABLED mode */
        if (ret)
                coresight_set_mode(csdev, CS_MODE_DISABLED);

        return ret;
}

static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
        struct etm_enable_arg arg = { };
        int ret;

        spin_lock(&drvdata->spinlock);

        drvdata->traceid = path->trace_id;

        /*
         * Configure the ETM only if the CPU is online.  If it isn't online
         * hw configuration will take place on the local CPU during bring up.
         */
        if (cpu_online(drvdata->cpu)) {
                arg.drvdata = drvdata;
                ret = smp_call_function_single(drvdata->cpu,
                                               etm_enable_sysfs_smp_call, &arg, 1);
                if (!ret)
                        ret = arg.rc;
                if (!ret)
                        drvdata->sticky_enable = true;
        } else {
                ret = -ENODEV;
        }

        if (ret)
                etm_release_trace_id(drvdata);

        spin_unlock(&drvdata->spinlock);

        if (!ret)
                dev_dbg(&csdev->dev, "ETM tracing enabled\n");
        return ret;
}

static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
                      enum cs_mode mode, struct coresight_path *path)
{
        int ret;

        switch (mode) {
        case CS_MODE_SYSFS:
                ret = etm_enable_sysfs(csdev, path);
                break;
        case CS_MODE_PERF:
                ret = etm_enable_perf(csdev, event, path);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static void etm_disable_hw(struct etm_drvdata *drvdata)
{
        int i;
        struct etm_config *config = &drvdata->config;
        struct coresight_device *csdev = drvdata->csdev;

        CS_UNLOCK(drvdata->csa.base);
        etm_set_prog(drvdata);

        /* Read back sequencer and counters for post trace analysis */
        config->seq_curr_state = (etm_readl(drvdata, ETMSQR) & ETM_SQR_MASK);

        for (i = 0; i < drvdata->nr_cntr; i++)
                config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));

        etm_set_pwrdwn(drvdata);
        coresight_disclaim_device_unlocked(csdev);

        CS_LOCK(drvdata->csa.base);

        dev_dbg(&drvdata->csdev->dev,
                "cpu: %d disable smp call done\n", drvdata->cpu);
}

static void etm_disable_sysfs_smp_call(void *info)
{
        struct etm_drvdata *drvdata = info;

        etm_disable_hw(drvdata);

        coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
}

static void etm_disable_perf(struct coresight_device *csdev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
                return;

        CS_UNLOCK(drvdata->csa.base);

        /* Setting the prog bit disables tracing immediately */
        etm_set_prog(drvdata);

        /*
         * There is no way to know when the tracer will be used again so
         * power down the tracer.
         */
        etm_set_pwrdwn(drvdata);
        coresight_disclaim_device_unlocked(csdev);

        CS_LOCK(drvdata->csa.base);

        coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);

        /*
         * perf will release trace ids when _free_aux()
         * is called at the end of the session
         */

}

static void etm_disable_sysfs(struct coresight_device *csdev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        /*
         * Taking hotplug lock here protects from clocks getting disabled
         * with tracing being left on (crash scenario) if user disable occurs
         * after cpu online mask indicates the cpu is offline but before the
         * DYING hotplug callback is serviced by the ETM driver.
         */
        cpus_read_lock();
        spin_lock(&drvdata->spinlock);

        /*
         * Executing etm_disable_hw on the cpu whose ETM is being disabled
         * ensures that register writes occur when cpu is powered.
         */
        smp_call_function_single(drvdata->cpu, etm_disable_sysfs_smp_call,
                                 drvdata, 1);

        spin_unlock(&drvdata->spinlock);
        cpus_read_unlock();

        /*
         * we only release trace IDs when resetting sysfs.
         * This permits sysfs users to read the trace ID after the trace
         * session has completed. This maintains operational behaviour with
         * prior trace id allocation method
         */

        dev_dbg(&csdev->dev, "ETM tracing disabled\n");
}

static void etm_disable(struct coresight_device *csdev,
                        struct perf_event *event)
{
        enum cs_mode mode;

        /*
         * For as long as the tracer isn't disabled another entity can't
         * change its status.  As such we can read the status here without
         * fearing it will change under us.
         */
        mode = coresight_get_mode(csdev);

        switch (mode) {
        case CS_MODE_DISABLED:
                break;
        case CS_MODE_SYSFS:
                etm_disable_sysfs(csdev);
                break;
        case CS_MODE_PERF:
                etm_disable_perf(csdev);
                break;
        default:
                WARN_ON_ONCE(mode);
                return;
        }
}

static const struct coresight_ops_source etm_source_ops = {
        .cpu_id         = etm_cpu_id,
        .enable         = etm_enable,
        .disable        = etm_disable,
};

static const struct coresight_ops etm_cs_ops = {
        .trace_id       = coresight_etm_get_trace_id,
        .source_ops     = &etm_source_ops,
};

static int etm_online_cpu(unsigned int cpu)
{
        if (!etmdrvdata[cpu])
                return 0;

        if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
                coresight_enable_sysfs(etmdrvdata[cpu]->csdev);
        return 0;
}

static int etm_starting_cpu(unsigned int cpu)
{
        if (!etmdrvdata[cpu])
                return 0;

        spin_lock(&etmdrvdata[cpu]->spinlock);
        if (!etmdrvdata[cpu]->os_unlock) {
                etm_os_unlock(etmdrvdata[cpu]);
                etmdrvdata[cpu]->os_unlock = true;
        }

        if (coresight_get_mode(etmdrvdata[cpu]->csdev))
                etm_enable_hw(etmdrvdata[cpu]);
        spin_unlock(&etmdrvdata[cpu]->spinlock);
        return 0;
}

static int etm_dying_cpu(unsigned int cpu)
{
        if (!etmdrvdata[cpu])
                return 0;

        spin_lock(&etmdrvdata[cpu]->spinlock);
        if (coresight_get_mode(etmdrvdata[cpu]->csdev))
                etm_disable_hw(etmdrvdata[cpu]);
        spin_unlock(&etmdrvdata[cpu]->spinlock);
        return 0;
}

static bool etm_arch_supported(u8 arch)
{
        switch (arch) {
        case ETM_ARCH_V3_3:
                break;
        case ETM_ARCH_V3_5:
                break;
        case PFT_ARCH_V1_0:
                break;
        case PFT_ARCH_V1_1:
                break;
        default:
                return false;
        }
        return true;
}

static void etm_init_arch_data(void *info)
{
        u32 etmidr;
        u32 etmccr;
        struct etm_drvdata *drvdata = info;

        /* Make sure all registers are accessible */
        etm_os_unlock(drvdata);

        CS_UNLOCK(drvdata->csa.base);

        /* First dummy read */
        (void)etm_readl(drvdata, ETMPDSR);
        /* Provide power to ETM: ETMPDCR[3] == 1 */
        etm_set_pwrup(drvdata);
        /*
         * Clear power down bit since when this bit is set writes to
         * certain registers might be ignored.
         */
        etm_clr_pwrdwn(drvdata);
        /*
         * Set prog bit. It will be set from reset but this is included to
         * ensure it is set
         */
        etm_set_prog(drvdata);

        /* Find all capabilities */
        etmidr = etm_readl(drvdata, ETMIDR);
        drvdata->arch = BMVAL(etmidr, 4, 11);
        drvdata->port_size = etm_readl(drvdata, ETMCR) & PORT_SIZE_MASK;

        drvdata->etmccer = etm_readl(drvdata, ETMCCER);
        etmccr = etm_readl(drvdata, ETMCCR);
        drvdata->etmccr = etmccr;
        drvdata->nr_addr_cmp = BMVAL(etmccr, 0, 3) * 2;
        drvdata->nr_cntr = BMVAL(etmccr, 13, 15);
        drvdata->nr_ext_inp = BMVAL(etmccr, 17, 19);
        drvdata->nr_ext_out = BMVAL(etmccr, 20, 22);
        drvdata->nr_ctxid_cmp = BMVAL(etmccr, 24, 25);

        coresight_clear_self_claim_tag_unlocked(&drvdata->csa);
        etm_set_pwrdwn(drvdata);
        etm_clr_pwrup(drvdata);
        CS_LOCK(drvdata->csa.base);
}

static int __init etm_hp_setup(void)
{
        int ret;

        ret = cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
                                        "arm/coresight:starting",
                                        etm_starting_cpu, etm_dying_cpu);

        if (ret)
                return ret;

        ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
                                        "arm/coresight:online",
                                        etm_online_cpu, NULL);

        /* HP dyn state ID returned in ret on success */
        if (ret > 0) {
                hp_online = ret;
                return 0;
        }

        /* failed dyn state - remove others */
        cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);

        return ret;
}

static void etm_hp_clear(void)
{
        cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
        if (hp_online) {
                cpuhp_remove_state_nocalls(hp_online);
                hp_online = 0;
        }
}

static int etm_probe(struct amba_device *adev, const struct amba_id *id)
{
        int ret;
        void __iomem *base;
        struct device *dev = &adev->dev;
        struct coresight_platform_data *pdata = NULL;
        struct etm_drvdata *drvdata;
        struct resource *res = &adev->res;
        struct coresight_desc desc = { 0 };

        drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata)
                return -ENOMEM;

        drvdata->use_cp14 = fwnode_property_read_bool(dev->fwnode, "arm,cp14");
        dev_set_drvdata(dev, drvdata);

        /* Validity for the resource is already checked by the AMBA core */
        base = devm_ioremap_resource(dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        desc.access = drvdata->csa = CSDEV_ACCESS_IOMEM(base);

        spin_lock_init(&drvdata->spinlock);

        drvdata->atclk = devm_clk_get_optional_enabled(dev, "atclk");
        if (IS_ERR(drvdata->atclk))
                return PTR_ERR(drvdata->atclk);

        drvdata->cpu = coresight_get_cpu(dev);
        if (drvdata->cpu < 0)
                return drvdata->cpu;

        desc.name  = devm_kasprintf(dev, GFP_KERNEL, "etm%d", drvdata->cpu);
        if (!desc.name)
                return -ENOMEM;

        if (smp_call_function_single(drvdata->cpu,
                                     etm_init_arch_data,  drvdata, 1))
                dev_err(dev, "ETM arch init failed\n");

        if (etm_arch_supported(drvdata->arch) == false)
                return -EINVAL;

        etm_set_default(&drvdata->config);

        pdata = coresight_get_platform_data(dev);
        if (IS_ERR(pdata))
                return PTR_ERR(pdata);

        adev->dev.platform_data = pdata;

        desc.type = CORESIGHT_DEV_TYPE_SOURCE;
        desc.subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_PROC;
        desc.ops = &etm_cs_ops;
        desc.pdata = pdata;
        desc.dev = dev;
        desc.groups = coresight_etm_groups;
        drvdata->csdev = coresight_register(&desc);
        if (IS_ERR(drvdata->csdev))
                return PTR_ERR(drvdata->csdev);

        ret = etm_perf_symlink(drvdata->csdev, true);
        if (ret) {
                coresight_unregister(drvdata->csdev);
                return ret;
        }

        etmdrvdata[drvdata->cpu] = drvdata;

        pm_runtime_put(&adev->dev);
        dev_info(&drvdata->csdev->dev,
                 "%s initialized\n", (char *)coresight_get_uci_data(id));
        if (boot_enable) {
                coresight_enable_sysfs(drvdata->csdev);
                drvdata->boot_enable = true;
        }

        return 0;
}

static void clear_etmdrvdata(void *info)
{
        int cpu = *(int *)info;

        etmdrvdata[cpu] = NULL;
}

static void etm_remove(struct amba_device *adev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(&adev->dev);

        etm_perf_symlink(drvdata->csdev, false);

        /*
         * Taking hotplug lock here to avoid racing between etm_remove and
         * CPU hotplug call backs.
         */
        cpus_read_lock();
        /*
         * The readers for etmdrvdata[] are CPU hotplug call backs
         * and PM notification call backs. Change etmdrvdata[i] on
         * CPU i ensures these call backs has consistent view
         * inside one call back function.
         */
        if (smp_call_function_single(drvdata->cpu, clear_etmdrvdata, &drvdata->cpu, 1))
                etmdrvdata[drvdata->cpu] = NULL;

        cpus_read_unlock();

        coresight_unregister(drvdata->csdev);
}

#ifdef CONFIG_PM
static int etm_runtime_suspend(struct device *dev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(dev);

        clk_disable_unprepare(drvdata->atclk);

        return 0;
}

static int etm_runtime_resume(struct device *dev)
{
        struct etm_drvdata *drvdata = dev_get_drvdata(dev);

        return clk_prepare_enable(drvdata->atclk);
}
#endif

static const struct dev_pm_ops etm_dev_pm_ops = {
        SET_RUNTIME_PM_OPS(etm_runtime_suspend, etm_runtime_resume, NULL)
};

static const struct amba_id etm_ids[] = {
        /* ETM 3.3 */
        CS_AMBA_ID_DATA(0x000bb921, "ETM 3.3"),
        /* ETM 3.5 - Cortex-A5 */
        CS_AMBA_ID_DATA(0x000bb955, "ETM 3.5"),
        /* ETM 3.5 */
        CS_AMBA_ID_DATA(0x000bb956, "ETM 3.5"),
        /* PTM 1.0 */
        CS_AMBA_ID_DATA(0x000bb950, "PTM 1.0"),
        /* PTM 1.1 */
        CS_AMBA_ID_DATA(0x000bb95f, "PTM 1.1"),
        /* PTM 1.1 Qualcomm */
        CS_AMBA_ID_DATA(0x000b006f, "PTM 1.1"),
        { 0, 0, NULL},
};

MODULE_DEVICE_TABLE(amba, etm_ids);

static struct amba_driver etm_driver = {
        .drv = {
                .name   = "coresight-etm3x",
                .pm     = &etm_dev_pm_ops,
                .suppress_bind_attrs = true,
        },
        .probe          = etm_probe,
        .remove         = etm_remove,
        .id_table       = etm_ids,
};

static int __init etm_init(void)
{
        int ret;

        ret = etm_hp_setup();

        /* etm_hp_setup() does its own cleanup - exit on error */
        if (ret)
                return ret;

        ret = amba_driver_register(&etm_driver);
        if (ret) {
                pr_err("Error registering etm3x driver\n");
                etm_hp_clear();
        }

        return ret;
}

static void __exit etm_exit(void)
{
        amba_driver_unregister(&etm_driver);
        etm_hp_clear();
}

module_init(etm_init);
module_exit(etm_exit);

MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
MODULE_DESCRIPTION("Arm CoreSight Program Flow Trace driver");
MODULE_LICENSE("GPL v2");